Method for producing a corner connection, connecting element for a corner connection, and corner connection

Abstract

The invention relates to a method for producing a corner connection (1) between two mitre-cut hollow-chamber profile portions (14, 14') using a connecting element (2) which has two legs (3, 3') arranged in an angled manner, depressions (4, 4') on the outer side of the legs (3, 3'), and a channel system (10) in the legs for guiding a thermoplastic connecting compound, which channel system (10) has inflow openings (7, 7') and also outlet openings (11, 11') which open into the depressions (4, 4'), the method comprising: (a) providing the portions (14, 14'); (b) incorporating through-openings through the walls of the hollow-chamber profile in such a way that the through-openings and the inflow openings (7, 7') of the channel system (10) are aligned when the legs (3, 3') have been introduced into a respective hollow chamber (13, 13') of the portions (14, 14'); (c) introducing the legs (3, 3') into a respective hollow chamber (13, 13') in such a way that the through-openings and the inflow openings (7, 7') are aligned, wherein cavities delimited by the depressions (4, 4') and inner walls of the hollow-chamber profile are formed; (d) introducing the connecting compound into the channel system (10) until the cavities delimited by the depressions (4, 4') and inner walls are at least partially filled with the connecting compound; and (e) solidifying the connecting compound. The invention also relates to a corresponding connecting element (2) and a corresponding corner connection (1).

Description

[0001] Method for producing a corner connection, connecting element for a corner connection and corner connection

[0002] The present invention relates to a method for producing a corner joint between two mitered sections of a hollow chamber profile, in particular a window and / or door hollow chamber profile, using a connecting element. Furthermore, the present invention also relates to a connecting element for such a corner joint and to such a corner joint.

[0003] Such corner joints between two mitered sections of a hollow chamber profile are known in the art, particularly in the field of window and door frames. Plastic windows and plastic doors made of thermoplastic materials, such as polyvinyl chloride (PVC), especially rigid PVC (PVC-II), are particularly widespread. Due to the thermoplastic properties of the material forming the hollow chamber profile sections, the sections are welded together in the miter area to form a corresponding corner joint. This welding can be carried out mechanically in four positions simultaneously using appropriate welding machines, thus forming a generally rectangular frame.Due to the lack of thermoplastic properties of the materials used to form the profiles, the mitered profile sections of metal profiles, particularly aluminum profiles, as well as metal composite profiles and other composite profiles, for example made of plastic materials with fibrous reinforcing elements, cannot be joined by welding. For example, the profile sections of such profiles are screwed together to form corner joints or connected to one another using appropriate fastening pins. In addition or alternatively, so-called corner connectors can also be used as mechanical connecting elements. Such corner connectors are connecting elements with two interconnected legs arranged at an angle to one another, which are inserted into hollow chambers of the corresponding profile sections and mechanically fastened, for example by screwing or pinning.The corner connectors can also be secured in the hollow chambers by gluing. The adhesive is applied to the corner connector before insertion into the profiles, providing an additional sealing effect in the finished corner connection. One such corner connector, which is both mechanically connected and glued to the hollow chamber profile, is described, for example, in DE 102004 016212 B4.

[0004] A disadvantage of such corner joints is that their production cannot currently be automated. Furthermore, when using adhesives, a curing time of several minutes is required before the corner joint can be subjected to load. Furthermore, the use of such sealing adhesives complicates the recycling process for such corner joints involving frames.

[0005] This is where the present invention comes in, which is based on the object of at least partially overcoming the disadvantages of the prior art. In particular, the method according to the invention should enable the rapid, reliable, and automated production of corner joints. Furthermore, the corner joint obtained by the method according to the invention should be easily recyclable.

[0006] These and other objects are achieved by a method having the features of claim 1, by a connecting element having the features of claim 7, and by a corner connection having the features of claim 11. Preferred embodiments of the method according to the invention, the connecting element according to the invention, and the corner connection according to the invention are each described in the dependent claims.

[0007] According to the present invention, it was recognized that a corner joint can be produced automatically, regardless of the material of the mitered profile sections of the hollow chamber profile. This is achieved by supplying a thermoplastic joining compound from the outside of the resulting corner joint through the connecting element already inserted into the hollow chambers of the profile sections. This creates a material-to-material bond between the connecting element and the interior of the hollow chamber of the profile section, into which the corresponding leg of the connecting element is inserted. For this purpose, a channel system with inlet openings for the joining compound to flow into the connecting element, as well as outlet openings that open into recesses on the surface of the connecting element, is provided inside the connecting element.Through-holes in the outer walls of the hollow chamber profile sections corresponding to the inlet openings of the connecting element are created in the hollow chamber profiles by mechanical means, for example, by milling, punching, or drilling. The thermoplastic joining compound then flows through the channel system inside the connecting element and emerges outward between the inner wall of the hollow chamber of the profile section and the recesses in the legs of the connecting element. There, the thermoplastic joining compound hardens or solidifies, thus creating a material-to-material bond between the connecting element and the hollow chamber profile section. In this way, the corner connection according to the invention is formed.

[0008] Accordingly, the present invention provides a method for producing a corner connection between two mitered sections of a hollow chamber profile, in particular a window and / or door hollow chamber profile, using at least one connecting element, wherein the connecting element comprises two legs arranged at an angle to one another and at least partially insertable into a hollow chamber of the hollow chamber profile, a plurality of recesses arranged on the outer side of the legs, and a channel system accommodated in the legs for guiding a thermoplastic connecting compound, wherein the channel system has inflow openings for the connecting compound to flow into the channel system and outlet openings that open into the recesses, wherein the method comprises the following steps:

[0009] (a) providing two mitred sections of a hollow chamber profile, in particular a window and / or door hollow chamber profile;

[0010] (b) Inserting through-holes through the walls of the hollow chamber profile in such a way that the through-holes and the inlet openings of the duct system are aligned when the legs of the connecting element are inserted into each hollow chamber of the two sections of the hollow chamber profile and fixed by means of a tool;

[0011] (c) inserting the legs of the connecting element into each hollow chamber of the two sections of the hollow chamber profile in such a way that the through openings and the inlet openings of the duct system are aligned, whereby cavities delimited by the recesses of the connecting element and the inner walls of the hollow chamber profile are formed;

[0012] (d) introducing a thermoplastic bonding compound through the through-openings into the channel system of the connecting element until the cavities defined by the recesses of the connecting element and the inner walls of the hollow chamber profile are at least partially filled with the thermoplastic bonding compound; and

[0013] (e) Solidification of the bonding compound.

[0014] Furthermore, the present invention provides a connecting element for a corner connection between two at least partially mitred sections of a hollow chamber profile, in particular a window and / or door hollow chamber profile, wherein the connecting element comprises two legs arranged at an angle to one another and at least partially insertable into a hollow chamber of the hollow chamber profile, a plurality of recesses arranged on the outer side of the legs, wherein the connecting element is characterized according to the invention in that it further comprises a channel system accommodated in the legs for guiding a thermoplastic connecting compound, wherein the channel system has inflow openings for the connecting medium to flow into the channel system and outlet openings which open into the recesses.Finally, the present invention also provides a corner connection between two at least partially mitred sections of a hollow chamber profile, in particular a window and / or door hollow chamber profile, which has been produced by the method according to the invention.

[0015] In the following, statements relating to the method according to the invention and emphasizing its advantages shall also apply equally to the connecting element according to the invention and to the corner connection according to the invention. Conversely, the statements relating to the connecting element according to the invention and the corner connection according to the invention shall also apply to the method according to the invention. Finally, the same applies to the statements relating to the connecting element according to the invention and the corner connection according to the invention, and vice versa.

[0016] According to the method according to the invention, profile sections of the desired length are first produced from rods of a hollow chamber profile, in particular a window and / or door hollow chamber profile, and each end is mitered. In particular, the miter angle is preferably 45° at both ends of the profile section. The hollow chamber profiles can be, for example, plastic hollow chamber profiles, for example made of thermoplastics such as polyvinyl chloride (PVC), in particular rigid PVC (PVC-U), and polyamides, in particular polyamide 6 or polyamide 6,6, metal profiles, in particular aluminum profiles, metal composite profiles, for example metal-plastic composite profiles, metal-wood composite profiles, or other composite profiles, for example made of plastic materials with fiber-containing reinforcing elements.Such plastic profiles with fiber-containing reinforcing elements are preferably extruded, pultruded, or pultruded-extruded hollow-chamber profiles made of a plastic matrix into which reinforcing fibers, such as continuous fibers or short and / or long fiber pieces, fabrics, and / or scrims, are integrated. The plastic matrix is ​​preferably a material coated with talc and / or chalk.The materials used here are preferably polyvinyl chloride (PVC), polyamide (PA), in particular polyamide-6 or polyamide-6,6, polyacrylonitrile styrene acrylate (ASA), polymethyl methacrylate (PMMA), polyacrylonitrile butadiene styrene polymers (ABS), polypropylene (PP), polyethylene (PE), polybutylene terephthalate (PBT), polyethylene terephthalate (PET) or even polyphenylene sulfide (PPS), polyetherimide (PEI) as well as mixtures, blends and copolymers, terpolymers, multiblock polymers and / or dendritic oligomers of the aforementioned materials. Fabrics, ribbons, knitted fabrics, woven fabrics, scrims and / or tapes, preferably inorganic glass fibers, carbon fibers or bio-based fibers such as wood fibers, cellulose or chemical fibers, whereby mixtures of two of the aforementioned fiber materials or all three fiber materials are also within the scope of the invention. However, glass fibers are particularly preferred.

[0017] Next, through-holes are created in the walls of the hollow-chamber profile, preferably by drilling, milling, pinning, or self-drilling screws with hollow chambers. The position of the through-holes is selected such that the through-holes and the inlet openings of the connecting element's channel system are aligned when the connecting element's legs are inserted into each hollow chamber of the two sections of the hollow-chamber profile. In this step of the process, additional openings can also be created in the walls of the hollow-chamber profile, for example, for the passage of fastening elements, preferably for pre-fixing the corner connection to be formed according to the invention.

[0018] The two legs of the connecting element are then each inserted into a hollow chamber of the corresponding section such that the through-holes through the outer walls of the hollow chamber profile and the inlet openings in the connecting element are aligned. Preferably, the dimensions of the connecting element are selected such that the outer side of the connecting element at least partially rests against the inner walls of the hollow chamber. In this way, cavities are formed between the recesses on the outer side of the connecting element and the inner walls of the hollow chamber. These cavities subsequently serve to accommodate part of the connecting compound.

[0019] In the subsequent step, the thermoplastic bonding compound is introduced into the corner joint to be formed according to the invention. In preferred embodiments of the method according to the invention, this takes place in a modified injection molding process. The unit comprising the mitered hollow chamber profile sections with the connecting element inserted into the hollow chambers is fixed in the injection molding device, and the bonding compound is injected inside the injection molding device through the through-openings into the inlet openings of the channel system of the connecting element. The material of the bonding compound is preferably selected such that, in the cured state, it forms a material-to-material bond both to the material of the connecting element according to the invention and to the interior of the hollow chamber of the hollow chamber profile used in the corner joint to be produced.The material of the joining compound is preferably a thermoplastic material that may contain fiber sections, in particular sections of glass fibers, carbon fibers, or aramid fibers. The amount of thermoplastic joining compound is selected such that a sufficiently stable connection according to the invention is formed and the joining compound does not cause the outer walls of the hollow-chamber profile to bulge outward and / or joining compound to leak through the miter joint of the corner connection. Suitable thermoplastic materials have proven particularly suitable for those materials mentioned in relation to the plastic matrix of the composite profile, which can be used as a hollow-chamber profile.Preferred materials for the thermoplastic bonding compound are therefore polyvinyl chloride (PVC), polyamide (PA), in particular polyamide 6 or polyamide 6,6, polyacrylonitrile styrene acrylate (ASA), polymethyl methacrylate (PMMA), polyacrylonitrile butadiene styrene polymers (ABS), polypropylene (PP), polyethylene (PE), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyetherimide (PEI), as well as mixtures, blends, and copolymers or terpolymers, multiblock polymers, and dendritic oligomers of the aforementioned materials. These materials are particularly preferably fiber-reinforced, in particular glass-fiber-reinforced, carbon-fiber-reinforced, or aramid-fiber-reinforced. The length of the individual fiber pieces is selected so that they do not unduly impede the introduction of the durable bonding compound into the corner joint to be created. Finally, the connecting compound solidifies in the formed corner joint.If an injection molding device is used, the corner connection can now be removed from the injection molding device.

[0020] In particularly preferred embodiments of the present invention, the method according to the invention is carried out simultaneously in different positions, so that several corner joints according to the invention are produced simultaneously. This preferably forms a peripheral frame, in particular a window or door frame.

[0021] With regard to the method according to the invention, it can be useful if, prior to step (d), the connecting element is pre-fixed by driving at least one fastening element through an outer wall of the respective section of the hollow chamber profile into the respective leg of the connecting element. Such pre-fixing can reduce the risk of the connecting compound widening the gap between the profile sections. Suitable screws, bolts or fastening pins can be used as fastening elements. It is advantageous if corresponding holes for the fastening elements are made in the outer wall of the hollow profile sections. It is also advantageous if corresponding receptacles for the fastening elements are provided in the legs of the connecting element. Alternatively or additionally, a clamping device for pre-fixing is also possible, which e.g.engages the fastening holes until the bonding compound hardens and is then released. Preferably, the pre-fixing tightens the connection by simultaneously applying force to all frame parts from the outside. This can preferably be achieved by pinning or screwing the connecting element to the profile sections, or by a detachable gripping device that engages the pinning holes until the bonding compound hardens and is then released again.

[0022] Additionally or alternatively, it may be advantageous if the connecting element has at least one joint recess in the joint area of ​​the two legs, into which a joint opening of the channel system opens, wherein the joint recess is at least partially filled with the thermoplastic joining compound in step (d). This seals the corner connection according to the invention in the joint area. It may also be preferred if the curable joining compound is in the form of a thermoplastic polymer compound. Thermoplastic polymer compounds can cure quickly, thus ensuring short cycle times in the automated implementation of the method according to the invention.In particular, polyvinyl chloride (PVC), polyamide (PA), especially polyamide-6 or polyamide-6,6, polyacrylonitrile styrene acrylate (ASA), polymethyl methacrylate (PMMA), polyacrylonitrile butadiene styrene polymers (ABS), polypropylene (PP), polyethylene (PE), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyetherimide (PEI), as well as mixtures, blends, and copolymers or terpolymers, multiblock polymers, and dendritic oligomers of the aforementioned materials have proven to be suitable materials as thermoplastic polymer compositions. These materials are particularly preferably fiber-reinforced, in particular glass fiber-reinforced, carbon fiber-reinforced, natural fiber-reinforced, or aramid fiber-reinforced. The plastic material of the hollow chamber profiles used to form the corner connection according to the invention is particularly preferably used as the plastic material of the thermoplastic polymer composition.The two plastic materials can be fiber-reinforced or not, independently of each other. This facilitates the recycling of the corner joint according to the invention after its intended use.

[0023] It may also be advantageous to preheat the connecting element, in particular the channel system of the connecting element, before step (d). This can particularly preferably be done by blowing hot air into the channel system of the connecting element. The hot air preferably has a temperature above 200°C. Preheating the connecting element prevents premature solidification of the thermoplastic joining compound.

[0024] With regard to the connecting element according to the invention, it may be preferred if each leg further comprises at least one receptacle for a fastening element for pre-fixing the connecting element to one of the sections of the hollow chamber profile. The corresponding receptacles serve to accommodate fastening elements, such as screws, bolts, or fastening pins, for pre-fixing the hollow chamber profile sections during the implementation of the method according to the invention.

[0025] It can also be helpful if the connecting element has at least one joint recess in the joint area of ​​the two legs, into which a joint opening of the channel system opens. This allows bare connecting compound to enter the joint recess during the process according to the invention, which, when cured, contributes to sealing the joint area of ​​the hollow chamber profile sections.

[0026] Metals, in particular aluminum and stainless steel, alloys, in particular an aluminum die-casting alloy, a zinc die-casting alloy and an aluminum-zinc die-casting alloy, acrylonitrile-styrene-acrylate (ASA), polyamides (PA), in particular PA-6 and PA-6,6, polyphenylsulfone (PPSII), polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PSU), polyphenylene sulfide (PPS), acrylonitrile-butadiene-styrene copolymer (ABS), polyoxymethylene (POM) and polyester carbonate (PESO), as well as copolymers and blends of these polymers, whereby these polymer materials can also be used in fiber-reinforced form, in particular glass fiber-reinforced, carbon fiber-reinforced or aramid fiber-reinforced form, have proven to be particularly suitable materials for the connecting element according to the invention. It is preferred that the connecting element be a component made of glass fiber-reinforced PA-6.

[0027] The connecting element according to the invention and the hollow chamber profile used in the method according to the invention, as well as individual parts thereof, can also be manufactured line by line or layer by layer using a line-by-line or layer-by-layer manufacturing process (e.g., 3D printing). However, the connecting element according to the invention is preferably manufactured by injection molding or die casting. The hollow chamber profiles are preferably manufactured by extrusion, pultrusion, or extrusion.

[0028] In the following, the present invention will be explained in detail with reference to the embodiments shown in the figures.

[0029] Figure 1 is a perspective view of a connecting element according to an embodiment of the present invention;

[0030] Figure 2 is a cross-sectional view of the connecting element according to the invention shown in Figure 1;

[0031] Figure 3 is a perspective view of a mitered hollow window chamber profile section, wherein a leg of a connecting element according to the invention as shown in Figure 1 is inserted into each of two hollow chambers of the profile section; and Figure 4 is a perspective view of the corner connection according to the invention formed.

[0032] The present invention is directed to a method for producing a corner connection 1, wherein such a connection 1 according to the invention comprises at least one connecting element 2 according to the invention. An embodiment of a connecting element 2 according to the invention is shown in a perspective view in Fig. 1.

[0033] According to the embodiment shown in Fig. 1, the connecting element 2 according to the invention is formed as an injection-molded part made of glass fiber-reinforced polyamide 6. According to this embodiment, the proportion of glass fibers in the material forming the connecting element 2 according to the invention is 30 wt.%.

[0034] In this embodiment, the connecting element 2 according to the invention is formed from two legs 3, 3' arranged at right angles to each other. Several recesses 4, 4' are located on the outer side of the connecting element 2. Such recesses 4, 4' are also located on the opposite outer side of the two legs 3, 3'. Furthermore, a joint recess 6 is arranged in the joint area 5 between the two legs 3, 3'.

[0035] In the embodiment of the connecting element 2 according to the invention shown in Fig. 1, on the narrow sides of the legs 3, 3' there are two inflow openings 7, 7' and a receptacle 8 for a fastening element 9.

[0036] The inlet openings 7, 7' open into a channel system 10, which can be clearly seen in the cross-sectional view of the connecting element 2 according to the invention shown in Fig. 1. The channel system 10 leads from the inlet openings 7, 7' to outlet openings 11, 11', which each open into recesses 4, 4', and to a butt opening

[0037] 12, which ends in the butt recess 6.

[0038] In Fig. 3 a situation of the method according to the invention is shown in which two connecting elements 2 according to Fig. 1 and Fig. 2 are each inserted with their leg 3' in hollow chambers

[0039] 13, 13' of a mitered section 14 of a hollow chamber profile. The connecting elements 2 are positioned such that the respective joint recess 6 of the connecting element 2 is located in the miter area of ​​the hollow chamber profile section 14. Furthermore, the outer sides of the connecting elements 2 partially rest against the inner walls of the hollow chambers 13, 13'. In the outer walls of the profile section 14 there are through-openings which are aligned with the inlet openings 7, 7' in the leg 3' of the connecting element 2 according to the invention. Furthermore, the section 14 has a further hole which is aligned with the receptacle 8 for a fastening element 9, but has a slight offset in the longitudinal direction for prestressing. The through-openings and the further hole can be created in the profile section 14, for example, by drilling using a CNC drilling center or using a suitable drilling jig.

[0040] A further hollow chamber profile section 14', which is mitered to match the profile section 14, is now pushed onto the respective free leg 3 of the connecting elements 2 in such a way that the free legs 3 of the connecting elements 2 in Fig. 3 engage in the corresponding hollow chambers 13, 13' of the hollow chamber profile section 14', wherein the outer sides of the legs 3 of the connecting elements 2 in turn partially rest against the inner walls of the hollow chambers 13, 13' of the hollow chamber profile section 14'.

[0041] The hollow chamber profile section 14' also has through-openings and a further hole in the outer walls, which correspond to those of the hollow chamber profile section 14. The hollow chamber profile section 14' is again positioned on the leg 3 of the connecting element 2 according to the invention in such a way that the respective butt recess 6 of the connecting element 2 is also located in the miter area of ​​the hollow chamber profile section 14'.

[0042] In the resulting arrangement, cavities are formed between the recesses 4, 4' on the outside of the respective connecting element 2 and the inner walls of the hollow chambers 13, 13', which subsequently serve to receive a part of the curable connecting compound to be injected into the arrangement.

[0043] In the embodiment shown, the hollow chamber profiles 13 for the sections 14, 14' are extruded profiles made of glass fiber reinforced polyamide-6.

[0044] To pre-fix the corner joint 1 to be formed, fastening pins 9 are now inserted into the receptacles 8 in the legs 3, 3' of the respective connecting element 2 according to the invention. Such pre-fixing can reduce the risk of the gap in the miter area of ​​the hollow chamber profile sections 14, 14' being enlarged during injection of the curable joining compound. The assembly comprising the two connecting elements 2 according to the invention and the mitered hollow chamber profile sections 14, 14' is then introduced into a corresponding injection molding device and fixed therein.In the injection molding device, a hardenable joining compound is then injected through the through-openings in the outer walls of the profile sections 14, 14' into the inlet openings 7, 7' in the legs 3, 3' of the connecting elements 2 and from there passes through the outlet openings 11, 11' into the cavities formed between the recesses 4, 4' and the inner walls of the hollow chambers 13, 13'. Furthermore, the hardenable joining compound also flows through the butt opening 12 into the butt recess 6. In the embodiment of the present invention shown, polyamide 6 was used as the hardenable joining compound. The solidification of the hardenable joining compound creates a material-to-material bond between the connecting elements 2 according to the invention and the hollow chamber profile sections 14, 14'. The hardenable connecting compound in the joint recess 6 effectively seals the mitre area of ​​the hollow chamber profile sections 14, 14' against the penetration of moisture.

[0045] After the curable joining compound has solidified, the corner joint 1 according to the invention thus formed can be removed from the injection molding device and the cast separated. The corner joint 1 thus formed is shown in a perspective view in Fig. 4. The corner joint 1 according to the invention has excellent corner fracture strength. Since both the hollow chamber profile sections 14, 14', the connecting elements 2 according to the invention, and the curable joining compound are based on the same plastic material, the recyclability of the corner joint 1 according to the invention is improved. Furthermore, the corner joint 1 according to the invention can be loaded immediately after the curable joining compound has solidified, so that no long curing times for the curable joining compound are required. Accordingly, short cycle times can be achieved in automated processes.

[0046] The present invention has been described in detail by way of example with reference to the embodiment of the present invention illustrated in the figures. It is understood that the present invention is not limited to the embodiments illustrated in the figures. Rather, the scope of the present invention arises from the appended claims. The figures illustrate a method for producing a corner connection of a window hollow chamber profile, a corresponding connecting element, and a corresponding corner connection of a window frame. Accordingly, the present invention is also explained with reference to such a corner connection for a window frame.It is understood that the present invention is also applicable accordingly to the production of other connections, for example a corner connection of a door frame, a post connection, a corner connection in automobile construction (car and / or truck construction), in refrigeration equipment construction (in particular refrigeration equipment frames), in air conditioning equipment construction as well as in aircraft and ship construction.

[0047] - Patent claims -

Claims

Method for producing a corner connection (1) between two mitred sections (14, 14') of a hollow chamber profile, in particular a window and / or door hollow chamber profile, using at least one connecting element (2), wherein the connecting element (2) comprises two legs (3, 3') arranged at an angle to one another and at least partially insertable into a hollow chamber (13, 13') of the hollow chamber profile, a plurality of recesses (4, 4') arranged on the outside of the legs (3, 3'), and a channel system (10) accommodated in the legs for guiding a thermoplastic connecting compound, wherein the channel system (10) has inflow openings (7, 7') for the connecting compound to flow into the channel system (10) and outlet openings (11, 11') which open into the recesses (4, 4'), wherein the method comprises the following steps includes: (a) providing two mitred sections (14, 14') of a hollow chamber profile, in particular a window and / or door hollow chamber profile; (b) introducing through-openings through the walls of the hollow chamber profile such that the through-openings and the inflow openings (7, 7') of the duct system (10) are aligned when the legs (3, 3') of the connecting element (2) are each introduced into a hollow chamber (13, 13') of the two sections (14, 14') of the hollow chamber profile; (c) introducing the legs (3, 3') of the connecting element (2) into a respective hollow chamber (13, 13') of the two sections (14, 14') of the hollow chamber profile such that the through openings and the inflow openings (7, 7') of the channel system (10) are aligned, whereby cavities delimited by the recesses (4, 4') of the connecting element (2) and inner walls of the hollow chamber profile are formed; (d) introducing a thermoplastic connecting compound through the through-openings into the channel system (10) of the connecting element (2) until the through-openings (4, 4') of the connecting element (2) and the inner walls of the hollow the cavities delimited by the chamber profile (3) are at least partially filled with the thermoplastic bonding compound; and (e) Solidification of the connecting compound. Method according to claim 1, characterized in that prior to step (d) the connecting element (2) is pre-fixed by driving at least one fastening element (9) through an outer wall of the respective section (14, 14') of the hollow chamber profile into the respective leg (3, 3') of the connecting element (2). Method according to claim 1 or claim 2, characterized in that the connecting element (2) has at least one butt recess (6) in the butt region (5) of the two legs (3, 3'), into which a butt opening (12) of the channel system (10) opens, wherein the butt recess (12) is at least partially filled with the thermoplastic connecting compound in step (d). Method according to one of claims 1 to 3, characterized in that the connecting compound is designed as a thermoplastic plastic compound.Method according to claim 4, characterized in that polyvinyl chloride (PVC), polyamide (PA), in particular polyamide-6 or polyamide-6,6, polyacrylonitrile styrene acrylate (ASA), polymethyl methacrylate (PMMA), polyacrylonitrile butadiene styrene polymers (ABS), polypropylene (PP), polyethylene (PE), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyetherimides (PEI) and mixtures, blends and copolymers or terpolymers, multiblock polymers and dendritic oligomers of the aforementioned materials are used as the thermoplastic plastic mass, wherein the aforementioned materials can also be fiber-reinforced, in particular glass fiber-reinforced, natural fiber-reinforced or aramid fiber-reinforced. Method according to one of claims 1 to 5, characterized in that the connecting element (2), in particular the channel system (10) of the connecting element (2), is preheated before step (d). Connecting element (2) for a corner connection (1) between two at least partially mitred sections (14, 14') of a hollow chamber profile, in particular a window and / or door hollow chamber profile, wherein the connecting element (2) comprises two legs (3, 3') arranged at an angle to one another and at least partially insertable into a hollow chamber (13, 13') of the hollow chamber profile, a plurality of recesses (4, 4') arranged on the outer side of the legs (3, 3'), characterized in that the connecting element (2) further comprises a channel system (10) accommodated in the legs (3, 3') for guiding a thermoplastic connecting compound, wherein the channel system (10) has inflow openings (7, 7') for the connecting medium to flow into the channel system (10) and outlet openings (11, 11') arranged in the recesses (4, 4').Connecting element (2) according to claim 7, characterized in that each leg (3, 3') further comprises at least one receptacle (8) for a fastening element (9) for pre-fixing the connecting element (2) to one of the sections (14, 14') of the hollow chamber profile. Connecting element (2) according to claim 7 or claim 8, characterized in that the connecting element (2) has at least one joint recess (6) in the joint area (5) of the two legs (3, 3'), into which a joint opening (12) of the channel system (10) opens.Connecting element (2) according to one of claims 7 to 9, characterized in that the connecting element is made as a component from a metal, in particular aluminum, stainless steel, an aluminum die-casting alloy, a zinc die-casting alloy and an aluminum-zinc die-casting alloy, acrylonitrile-styrene-acrylate (ASA), a polyamide (PA), in particular PA-6 and PA-6,6, acrylate polymers (PMMA), polyetherimides (PEI), polyphenylsulfone (PPSU), polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PSU), polyphenylene sulfide (PPS), acrylonitrile-butadiene-styrene copolymer (ABS), polyoxymethylene (POM) and polyester carbonate (PESO) as well as a copolymer or blend of these polymers, wherein these polymer materials can also be fiber-reinforced, in particular glass fiber-reinforced or aramid fiber-reinforced, and / or with fillers, in particular talc, chalk, hollow glass spheres, glass spheres, glass plates. Corner connection (1) between two at least partially mitered sections (14, 14') of a hollow chamber profile, in particular a window and / or door hollow chamber profile, produced by a method according to one of claims 1 to 6. Corner connection (1) according to claim 11, characterized in that the hollow chamber profile is a plastic hollow chamber profile, preferably made of thermoplastics such as polyvinyl chloride (PVC), in particular rigid PVC (PVC-U), and polyamides, in particular polyamide 6 or polyamide 6,6, as a metal profile, preferably as an aluminum profile, as a metal composite profile, preferably as a metal-plastic composite profile, metal-wood composite profile or as another composite profile, preferably made of plastic materials with fiber-containing reinforcing elements.

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